In a history of stereoscopic image display, Charles Wheatstone published a first stereoscopic image technology in England in 1836. Thereafter, with development of a photograph technology, a stereoscopic image processing technology employing a parallax barrier and a lenticular lens was developed in the early 20th century, thereby opening a new age of a stereoscopic image. In the middle 20th century, a holographic image processing technology was introduced to suggest anew principle of a stereoscopic image. Recently, a spectacle type stereoscopic image processing technique using a chromatic aberration or a polarizing filter, a synchronous shutter technique of providing time-divisional images, a technique using a head mount set, and the like were suggested.
The stereoscopic image processing technique using a hologram is hardly put into practice for processing digitalized image information. Examples of a stereoscopic image processing technique using spectacles include an anaglyph technique using color spectacles, a polarizing spectacle technique, and a synchronous shutter spectacle technique. These techniques are not widely used for the reason of inconvenience due to the wearing of special spectacles, a sanitary problem, a bad influence on a human body, and the like.
Recently, techniques not using spectacles were actively studied. A representative technique not using spectacles is a lenticular technique and a parallax barrier technique. In the lenticular technique, a lenticular lens plate in which cylindrical lenses are vertically arranged is disposed in the front of an image display panel. In the parallax barrier technique, a parallax barrier in which a kind of strip pattern is formed is disposed in the front of an image display panel.
Recently, with wide spread of a thin film transistor (TFT) liquid crystal display (LCD), stereoscopic image display apparatus embodied by coupling a parallax barrier to the TFT LCD were suggested.
The main reason for not putting the stereoscopic image display apparatus using a parallax barrier is that a visible distance is too large to be applicable to a screen of a computer monitor or a mobile phone. Many studies for solving the problem have been made, but a good performance was not obtained in the art.
The inventor of the present invention suggested a 2D/3D convertible stereoscopic image display apparatus which can markedly reduce the visible distance and which can be put into practice at low cost, which is disclosed in PCT/KR03/01415 and PCT/KR03/01537. The 2D/3D convertible stereoscopic image display apparatus described in these applications are omitted.
On the other hand, it should be noted that a stereoscopic image display apparatus in the following description means a 2D/3D convertible stereoscopic image display apparatus and the stereoscopic image display apparatus can be embodied as the 2D/3D convertible stereoscopic image display apparatus.
The stereoscopic image display apparatus according to the prior applications has a problem.
The problem of the prior application is described with reference to FIGS. 1 to 3.
Referring to FIG. 1, in the known 2D image display panel which is generally used in a computer monitor, RGB pixels (sub pixels) form a unit pixel, the unit pixels are arranged in a matrix pattern, and an image (2D image) is displayed by actively driving the unit pixels. The concepts of the 2D image and the 3D image (stereoscopic image) should be clearly understood for the purpose of understanding the invention. The 2D image means that a left eye and a right eye recognize the same image. In other words, even an image exhibiting a stereoscopic effect in software by the use of a perspective feeling or the like is not the 3D image nut the 2D image, because the left eye and the right eye recognize the same image. The stereoscopic image means an image obtained by allowing the left eye and the right eye to recognize a left-eye image and a right-eye image which are different from each other by a difference in viewing angle.
FIG. 2 is a diagram illustrating a known linear parallax barrier. FIG. 3 is a diagram illustrating a known 2D/3D convertible image display panel (hereinafter, briefly referred to as “image display panel”). It will be understood by those skilled in the art that scales are different from actual ones in FIGS. 2 and 3 for the purpose of easily understanding the invention. The parallax barrier shown in FIG. 2 is spaced apart from the image display panel by a certain distance. The same is true of all the subsequent drawings. In the image display panel shown in FIG. 3, the RGB pixels are classified into the left-eye pixels and the right-eye pixels. As shown in FIG. 6, the RGB pixels may be set as a unit pixel and the unit pixels may be classified into the left-eye pixels and the right-eye pixels. The technique of providing a stereoscopic image by classifying the RGB pixels into the left-eye pixels and the right-eye pixels is disclosed in PCT/KR03/01537 and the like and several problems to be solved for embodying the technique are also described in detail in the above-mentioned application. That is, an image focused through the parallax barrier is divided into the left-eye image and the right-eye image to embody a stereoscopic image. This stereoscopic image embodying method is similarly used in the following description. The technique of providing a stereoscopic image by using RGB pixels as a unit pixel and classifying the unit pixels into the left-eye pixels and the right-eye pixels is disclosed in PCT/KR03/01415.
In order to obtain a stereoscopic image, the linear parallax barrier shown in FIG. 2 is disposed in the front of the image display panel shown in FIG. 3 so as to be apart by a certain distance from each other. Specifically, the left-eye pixels and the right-eye pixels of the image display panel are disposed in a linear pattern and the linear patterns are alternately arranged. The parallax barrier for distinguishing the left-eye image and the right-eye image is configured accordingly in a strip pattern. FIG. 4 is a diagram illustrating a left-eye image formed by the linear parallax barrier shown in FIG. 2 and the image display panel shown in FIG. 3. FIG. 5 is a diagram illustrating a right-eye image formed by the linear parallax barrier shown, in FIG. 2 and the image display panel shown in FIG. 3.
As shown in FIGS. 4 and 5, since strip patterns are formed in the left-eye image and the right-eye image, the strip patterns are also formed in the stereoscopic image recognized by a person. Although the strip patterns are exaggerated in FIGS. 4 and 5, but a person having a normal sight can recognize the strip patterns and thus feels uneasy.
FIG. 6 is a diagram illustrating another known image display panel. FIG. 7 is a diagram illustrating a left-eye image formed by the linear parallax barrier shown in FIG. 2 and the image display panel shown in FIG. 6. FIG. 8 is a diagram illustrating a right-eye image formed by the linear parallax barrier shown in FIG. 2 and the image display panel shown in FIG. 6. This example indicates the technique of providing a stereoscopic image by using RGB pixels as a unit pixel and classifying the unit pixels into the left-eye pixels and the right-eye pixels as described above.
Similarly to FIGS. 4 and 5, since strip patterns are formed in the left-eye image and the right-eye image, the strip patterns are also formed in the stereoscopic image recognized by a person. A person having a normal sight can recognize the strip patterns and thus feels uneasy. In this case, a stereoscopic image can be obtained. However, since the RGB pixels which are sub pixels are used as a unit pixel, there is a problem in that a color mixing phenomenon occurs and thus a color tone is less clear than that of the stereoscopic image shown in FIGS. 4 and 5 and embodied at a sub pixel level.
The strip patterns formed in the image displayed by the known stereoscopic image display apparatus are inevitably formed due the strip patterns of the parallax barrier.
It is widely known in the art that the left-eye pixels and the right-eye pixels of the image display panel are configured in a linear pattern and arranged alternately to configure the parallax barrier for distinguishing the left-eye image and the right-eye image in the strip patterns.
The inventor of the present invention intends to solve the above-mentioned problems by providing an image display panel and a parallax barrier, in which left-eye pixels and right-eye pixels of the image display panel are not configured in a linear pattern and the parallax barrier is not configured in a strip pattern.